The goal of this clinical trial is to compare immune responses to different influenza vaccine formulations in older adults and to understand how immune aging and repeated annual influenza vaccination affect these responses.
The main questions it aims to answer are:
* Do standard dose, MF59 adjuvanted, and high dose influenza vaccines produce different immune responses in adults aged 65 years or older? * How does immune aging affect responses to different influenza vaccine formulations? * How do immune responses change with repeated annual influenza vaccination, and do these changes differ among vaccine formulations?
Researchers will compare older adults who receive a standard dose, MF59 adjuvanted, or high dose influenza vaccine. Younger adults aged 19-49 years who receive a standard dose influenza vaccine will also be included as a reference group to help evaluate age related differences in immune responses.
Participants will:
* Receive an influenza vaccine. * Provide blood samples before and after vaccination to measure antibody and other immune responses. * Some participants will provide additional blood or nasal samples for more detailed evaluation of immune responses.
Older adult group: aged 65 years or older
Younger reference group: aged 19 to 49 years
Able to receive influenza vaccination and complete the scheduled follow up
Receipt of an influenza vaccine or any other vaccine within 4 weeks prior to enrollment
Immunocompromised status, including ongoing chemotherapy or immunosuppressive therapy, high dose corticosteroid therapy, history of solid organ or hematopoietic stem cell transplantation, active malignancy, HIV infection, or other clinically significant immunocompromising conditions
Moderate or severe acute infection
History of allergic reaction to an influenza vaccine or any of its components, or any other condition that precludes influenza vaccination
Parallel
Standard dose influenza vaccine
Biological/VaccineA single intramuscular dose of standard dose influenza vaccine administered according to the approved prescribing information.
MF59 adjuvanted influenza vaccine
Biological/VaccineA single intramuscular dose of MF59 adjuvanted influenza vaccine administered according to the approved prescribing information.
High dose influenza vaccine
Biological/VaccineA single intramuscular dose of high dose influenza vaccine administered according to the approved prescribing information.
Geometric mean titers of hemagglutination inhibition antibodies at 1 month after vaccination
Geometric mean titers (GMTs) of hemagglutination inhibition antibodies against each influenza vaccine strain will be assessed at 1 month after vaccination.
Geometric mean fold rise in hemagglutination inhibition antibody titers at 1 month after vaccination
Geometric mean fold rises (GMFRs) in hemagglutination inhibition antibody titers from baseline to 1 month after vaccination will be assessed for each influenza vaccine strain.
Seroconversion rate following influenza vaccination
The proportion of participants achieving a prespecified serologic response, defined as a fourfold or greater increase in hemagglutination inhibition antibody titer from baseline, will be assessed for each vaccine strain.
Frequency of influenza specific B cells following vaccination
The frequency of influenza specific B cells will be assessed at baseline, 1 week, and 1 month after vaccination. Responses will be compared among vaccine formulations and evaluated according to age and repeated annual vaccination.
normalized level of influenza specific secretory IgA in nasal samples
Influenza specific secretory IgA will be measured in nasal samples and normalized to total protein concentration measured using the BCA assay. Normalized secretory IgA levels will be used to assess mucosal immune responses. A pilot assessment will be conducted during the first vaccination season, followed by assessment before and 1 month after vaccination during subsequent annual vaccination seasons to evaluate changes associated with repeated vaccination.
Frequency of influenza specific T cells following vaccination
Influenza specific T cell responses will be assessed by measuring the frequency of antigen responsive T cells following stimulation with influenza antigens. Antigen specific T cells will be characterized using activation induced and functional markers.
Molecular immune signatures associated with influenza vaccine responses
Transcriptomic, miRNA, and proteomic analyses will be performed at selected time points to identify molecular signatures associated with vaccine induced immune responses, vaccine formulation, aging, and repeated annual vaccination. Integrated multiomics analyses will be used to explore molecular pathways and potential biomarkers associated with vaccine responsiveness.
Extracellular vesicle associated molecular signatures following influenza vaccination
Molecular profiles of extracellular vesicles, including exosomes, will be explored to identify biomarkers associated with vaccine induced immune responses, immune aging, and repeated annual vaccination.
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Korea University Guro Hospital
Lead sponsor
National Research Foundation of Korea
Collaborator
